三种不同元素掺杂的碳点与DNA相互作用及其机制研究

碳点(carbon dots,CDs)在材料学及生物医学相关领域的研究已引起科研人员的广泛关注.本文采用一步水热法,制备了三种具有不同元素掺杂的CDs、N-CDs、N,S-CDs,并结合多种光谱法、熔链温度法和黏度法,系统地研究了三种不同元素掺杂的碳点与ctDNA结合模式以及结合能力的差异.荧光实验证明三种不同性质的碳点CDs、N-CDs、N,S-CDs与ctDNA的相互作用模式为沟槽结合,结合力主要为氢键和范德华力,并伴随着轻微的静电作用力.在强电解质和变性剂的存在下,会减弱碳点与ctDNA之间的沟槽结合.圆二色光谱实验和红外光谱实验反映了碳点与ctDNA的沟槽结合作用并不会明显改变ctDNA的构象.与未掺杂的碳点(CDs)相比,氮硫元素的掺杂可使N,S-CDs与ctDNA的沟槽结合能力减弱,但是加大碳点表面电荷,可增强N-CDs与ctDNA的结合.这一结论为碳点的设计及其在生物医学领域中的应用提供了理论参考.

Interactions and mechanisms of three different element doped carbon dots with DNA

Carbon dots(CDs)have attracted great attention in the field of materials science and biology.In this paper,three kinds of CDs with different doping elements were synthesized by one-step hydrothermal method.The binding modes and binding capacities of ctDNA and carbon dots doped with three different elements were systematically studied by means of multispectral method,melt chain temperature method and viscosity method.Fluorescence experiments have proved that the interaction modes of CDs,N-CDs and N,S-CDs with ctDNA were groove binding,and the binding force was mainly hydrogen bond and van der Waals interaction,accompanied by slight electrostatic force.In the presence of strong electrolytes and denaturants,the groove binding between carbon dots and DNA was weakened.Circular dichroic spectroscopy and FTIR spectroscopy showed that the groove binding of carbon dots and DNA did not significantly change the conformation of DNA.It was worth noting that compared with undoped carbon dots(CDs),doping with nitrogen and sulfur could weaken the groove binding ability of N,S-CDs and ctDNA.However,increasing the surface charge of carbon points could enhance the binding of N-CDs to ctDNA.This conclusion is expected to provide a theoretical reference for the design of targeted carbon dots in the biomedical field in the future.